slint 1.12: with_winit_window return None

[CarbonPool]

Bug Description

let ui = AppWindow::new()?;
ui.window().with_winit_window(|window: &Window| {
        
}).unwrap();

Error: called Option::unwrap() on a None value. It seems that this prompt was not available in the previous version.

Reproducible Code (if applicable)

Environment Details

• Slint Version:
• Platform/OS:
• Programming Language:
• Backend/Renderer:

Product Impact

No response

[ogoffart]

That means that there are no winit window for this this window.

Likely because this is not using the winit backend.

What platform are you on. Maybe on Linux where the Qt backend is the default.
Make sure you initialize the winit backend with BackendSelector::backend_name as explained in
https://docs.slint.dev/latest/docs/rust/slint/winit_030/

I hope this helps.

[tronical]

With the provided code snippet, with_winit_window() would fail even if the winit backend was selected, because the winit window doesn't exist yet. I'll add something to the docs to expand on this.

[tronical]

I made a doc PR for this: #8727

[CarbonPool]

I added: slint::BackendSelector::new().backend_name("winit".into()).select().unwrap();

The error still exists. I use the Windows platform and I confirm that version 1.11 runs normally.